Question

For the reaction, $N_2+3H_2\rightleftharpoons 2N{H}_3$, the rate of change of concentration for hydrogen is $0.3\times {10}^{-4}M{s}^{-1}$.
The rate of change of concentration of ammonia is (in $M{s}^{-1}$):

• A. $-0.2\times {10}^{-4}$
• B. $0.2\times {10}^{-4}$
• C. $0.1\times {10}^{-4}$
• D. $0.3\times {10}^{-4}$

Answer 1

The correct option is B $0.2\times {10}^{-4}$

$N_2+3H_2\rightleftharpoons 2N{H}_3$
$\frac{d{H}_2}{dt}=-0.3\times {10}^{-4}M{s}^{-1}$
$Rate=-\frac{1}{3}\frac{d{H}_2}{dt}=+\frac{1}{2}\frac{dN{H}_3}{dt}$
$=\frac{dN{H}_3}{dt}=-\frac{2}{3}\frac{d{H}_2}{dt}$
$=-\frac{2}{3}\times -0.3\times {10}^{-4}$
$=0.2\times {10}^{-4}$